Check VectorClock for common case first and cache hashCodes. See #3441
Make ClusterDaemon a bit more testable. See #3441
Changing VectorClock and GossipOverview to TreeMaps. See #3441
Make VectorClock private[cluster] and remove unused code. See #3441
* Removed leader commands for Shutdown and Exit
* Member shutdown itself when it sees itself as Exiting
* Singleton cluster with status Exiting will shutdown itself,
in case the Exiting gossip never arrives
* Exiting member not part convergence check
* Exiting member is removed by leader (on convergence) when the
exiting member is in the unreachable set, i.e. sucessfully shutdown
* Reverted the change made for #3266, i.e. Exiting is
detected as unreachable again.
* Adjust ClusterSingletonManager to new Exiting behaviour
* Fix bug in HeartbeatSender, which caused it to continue to
send heartbeats to removed nodes, instead of rebalancing
* Refactoring of leaderActions method
* Leaving section in docs
* Assign internal upNumber when member is moved to Up
* Public API Member.isOlder
* Change cluster singleton to use oldest member instead of leader
* Update samples and docs
* When seen same the gossip chat is initated with GossipStatus
message containing the vclock only
* Remove conversation flag in GossipEnvelope
* Ordinary tell instead of actorSelection when replying
* Disallow join requests when already part of a cluster
* Remove wipe state when joining, since join can only be
performed from empty state
* When trying to join, only accept gossip from that member
* Ignore gossips from unknown (and unreachable) members
* Make sure received gossip contains selfAddress
* Test join of fresh node with same host:port
* Remove JoinTwoClustersSpec
* Welcome message as reply to Join
* Retry unsucessful join request
* AddressUidExtension
* Uid in cluster Member identifier
To be able to distinguish nodes with same host:port
after restart.
* Ignore gossip with wrong uid
* Renamed Remove command to Shutdown
* Use uid in vclock identifier
* Update sample, Member apply is private
* Disabled config duration syntax and cleanup of io settings
* Update documentation
